| 摘要 |
<p>The trencher of the present invention includes a wheeled carriage (12) which has a steering mechanism and a digging chain (72) which operates along an upright path. The trencher includes an upright boom structure (60) that is mounted to the carriage and a digging chain support frame (64) that can be raised and lowered relative to the trencher along an upright path. The digging chain (72) is mounted to the digging chain support frame (64) by a powered sprocket wheel (70) and a freely turning pulley wheel (71). The sprocket wheel (70) and the pulley wheel (71) are positioned so that the digging chain describes an upright path. The path described by the digging chain is sufficiently upright so that the trencher can excavate a curved trench without the digging chain interfering with the walls of the trench to a degree that is sufficient to impede the operation of the trencher.</p> |
